I’ve been playing this game for a while in the Alpha 16 and It’s very satisfying the tools for making the mines and the option to cut the land and see inside.
With that in mind, why not put some furniture or itens for Dungeon creation? You could make your own Dungeon to protect your gold and goods, could be something very interesting for Dwarf Class or Goblin Class… The Mason or the Blacksmith could make the traps added with venom made with the herbalists.
With this and some more options of characters control you could make Dungeons in the map for players to venture and find unique itens and strong enemies to battle. This would make the game much more worth exploring and Fun. The same way the enemies with constructions appear a Dungeons in the mountain sides could appear spawning monsters and creating the necessities for the heroes to explore.
A job of Dungeon Master could be made in order to create the traps, or to spawn minions with magic to defend the Dungeons too. In the end it’s just my suggestion to the game!